In women with mild stress incontinence (mean urine loss of 3.7 g/h), pelvic floor training using vaginal cones resulted in a subjective success rate of 70% (19/27), that is complete cure or reduction by >50% of the original severity. However, in women with severe stress incontinence (mean urine loss of 20.7 g/h) cone therapy was successful in only 14% (7/50). The predictive value of six parameters (age, parity, urine loss by pad test, frequency of incontinence, contractile strength of the vagina, and perceived problems) was analyzed and two showed significant prognostic values: a smaller amount of urine loss and less frequent incontinence. It is concluded that vaginal cone therapy is one physical treatment option for stress incontinence but is of no clinical effect for those with severe incontinence.